1. Field of the Invention
The present invention relates generally to the field of devices for flushing catheters. More specifically, the present invention discloses a thumb-powered flushing device for intravenous catheters.
2. Statement of the Problem
Intravenous catheters have been widely used for many years to administer medications and other fluids to patients. In some instances, medication is administered through the catheter on a continuous basis. However, in other instances, doses of medication are administered on a periodic basis. Patients undergoing long-term drug therapies (i.e., a few to several weeks) will typically have a catheter or xe2x80x9cportxe2x80x9d surgically installed to facilitate multiple infusions or injections. One of the biological reactions of the body to an implanted catheter is a growth of dendrites or filaments into the end of the catheter. Thus, an important aspect of this process is maintaining an open, free-flowing catheter.
When administering periodic doses of medication, one conventional approach has been to maintain a low-volume, constant flow of saline solution or other fluid (typically in the range of approximately 0.1 to 5.0 ml/hr) through the catheter between doses of medication. This small continual flow, also known as the KVO (keep vein open) flow, helps to keep the catheter and the patient""s vein open. The KVO infusion can be provided by an electronic pump, disposable infuser, or an IV drip. The IV line attached to the KVO device typically terminates in an injection site (e.g., a Y-site as illustrated in FIG. 1) at the patient. In the case of a conventional Y-site, one branch of the Y-site has a rubber seal that permits medication or other fluids to be injected from a syringe through the rubber seal and into the catheter, without the need to disconnect the KVO flow.
The KVO flow is sometimes insufficient to maintain patency of the catheter. Therefore, many healthcare professionals inject a quantity of saline solution (about 3 ml) via syringe through the rubber seal of the Y-site to ensure patency of the catheter prior to administering each dose of medication. Several of these flushes may be required each day, usually just prior to injections of medication. This approach is effective, but adds time and expense to the procedure.
The prior art in the field also includes the following flushing devices for catheters:
Cole et al. disclose a catheter flushing device with a valve plunger having a capillary passage that provides a first low-flow path. When the plunger is moved from its seat, a second high-flow path is established that flushes the apparatus. Stevens discloses a similar device.
Reynolds et al. disclose a flush device for an intravenous blood pressure monitoring system that includes a continuous flow channel and a fast flush channel. In particular, the flush device has a generally tubular housing containing a plunger surrounded by an elastomeric member. When the plunger is in its raised position, the elastomeric member is relaxed and restricts flow through the housing to a small capillary channel. When the plunger is depressed, the elastomeric member stretches and creates a larger channel for fluid flow between the elastomeric member and the interior surface of the housing, which permits a fast flush flow through the device.
Steigerwald, Hubbard et al., and Le disclose other examples of catheter flushing devices with push-button valve mechanisms that provide both slow flow and fast flush modes.
Bryant et al. disclose an ambulatory infusion system having a gas-pressurized bladder to discharge solution from an adjacent bag. Internal gas pressure is developed within the bladder by a chemical reaction. The tubing set leading from the solution bag includes a flow restrictor that can be sized to provide minimal flow rates.
3. Solution to the Problem
None of the prior art references uncovered in the search show a catheter flushing device using a thumb-powered movable member (e.g., a flexible diaphragm) to propel fluid through the catheter, and a valve that regulates flow into and out of the chamber beneath the movable member. This configuration has significant safety advantages in that it prevents accidental backflow or uncontrolled forward flow through the device to the patient. The present device can be used to deliver a small quantity of fluid to flush a catheter, or alternatively can be used to deliver a bolus of medication. The present device can also be used to provide a continuous low-volume flow (i.e., a KVO flow) to the catheter between doses.
This invention provides a catheter flushing device that includes a chamber covered with a movable member (e.g., a flexible diaphragm) that can be compressed by exertion of pressure on the movable member; and a valve having a first position allowing fluid from a fluid source to fill the chamber, and a second position allowing fluid from the chamber to flow through the catheter when pressure is exerted on the movable member. In particular, the catheter flushing device includes a housing having a cylindrical valve opening, an inlet port for connection with the fluid source, and an outlet port for connection with the catheter. The chamber is defined by a movable member sealed to a region of the housing. The chamber can be compressed by manually exerting pressure on the movable member by means of a thumb or finger. A passageway extends through the housing from the chamber to the valve opening. A rotatable valve member within the valve opening has a channel directing fluid from the inlet port into the chamber in the first position, and a channel directing fluid from the chamber to the outlet port in the second position. The device can also be equipped with a KVO flow path through the housing between the inlet and outlet ports to maintain a substantially constant, minimal flow from the fluid source to the catheter that bypasses the valve assembly.
These and other advantages, features, and objects of the present invention will be more readily understood in view of the following detailed description and the drawings.